1. The Field of the Invention
The present invention relates to installing wire, cables (such as fiber optic cables or communications cables), or the like. More specifically, the present invention relates to a device for gripping a wire, cable, or similar object so as to enable that object to be pulled through a conduit or other enclosure to install the object.
2. State of the Art
Wires, cables, and the like are commonly installed by pulling the same through a conduit. Industrial or commercial construction of buildings commonly involves placing conduits in the walls of the building and installing wires or cables in the conduit after construction of the wall has been completed. Similarly, municipal wires and cables are often pulled through underground conduits in order to install the cables. Herein, the term wire is used to describe the various types of wires, cables, and the like which are similarly pulled through conduits to install the same.
When installing wires, a rope or other pulling line is first threaded through the conduit. One end of the pulling line is then connected to the wire, and a pulling machine is attached to the other end of the pulling line and used to pull the wire through the conduit via the pulling line. The pulling machine will typically exert a force of a thousand pounds or more in order to pull the wire through the conduit. Lengthy conduits, bends in the conduit, and the stiffness of the wire itself all contribute to the high pulling force required to pull wires through a conduit.
In municipal applications such as underground power lines or communications lines, the wires being installed are typically larger than those used in commercial buildings, and require a very high pulling force in order to successfully install the desired wire into the conduit.
When installing a wire, it is highly desirable to successfully install the wire without losing the connection between the pulling line and the installed wire. If the connection between the pulling line and installed wire is lost during a pull, it is typically impossible to reconnect the wire and pulling line inside of the conduit. As such, the wire must be removed from the conduit and the pull must be started again from the beginning. It is typically impossible to remove the wire from the conduit without damaging the wire. Because of the space constraints (especially in underground municipal applications), it is typically necessary to attach a pulling line to the wire every few yards while the wire is pulled a section. Attachment to the wire typically pierces the insulation or otherwise damages the wire and renders the wire unusable. Where multiple wires are being pulled at once through a conduit, all of the wires must be removed from the conduit and are typically thereafter unusable.
It is thus appreciated that losing connection between the pulling line and the wire results in both a significant loss of time and a significant monetary loss in the unusable wire. The larger wires used in municipal installations may cost several thousands of dollars for a single run of wire. It can be appreciated that it is necessary to have a secure and reliable connection between the pulling line and the installed wire.
It is also necessary to have a connection between the pulling line and installed wire which is able to reliably transmit thousands of pounds of force between the pulling line and the installed wire. It is desirable that the connection between the pulling line and installed wire be able to remain connected throughout the pull even if tension is temporarily lost or varies through out the pull, and should be able to remain connected regardless of the orientation of the connection between the pulling line and wire. It is particularly desirable to have a connector which remains easy and convenient to use while providing a secure attachment capable of transmitting a very high force to the wire.
It is thus desirable to have a connector which is capable of connecting a pulling line and a wire securely and reliably. It is desirable to have a connector which is capable of transmitting very high pulling forces between the pulling line and wire reliably. It is desirable to have a connector which remains securely connected to the pulling line and wire even if tension is lost and regardless of the orientation of the connector. It is desirable to have a connection which remains easy to use while providing a more secure and reliable operation.